Dental instrument



Jan. l5, 1963 H.,s. BRENMAN ETAL 3,073,03'1

DENTAL INSTRUMENT Filed March 29, 1960 w .p M .b M 4 6 w 5 4 1 /IB///////,`l 3 m 2 5 2 Fig.

IN V EN TOR. HENRY S. BRENMAN SEMOND LEVITT ATTORNEY V3,073,031yPatented Jan. 15, 1963 United States Patent Office 3,073,031 Y DENTALINSTRUMENT Henry' S. Brenmau, 1913 Walnut St., Philadelphia, Pa., andSemond Levitt, 1835 Lippincott Road, Huntington Valley, Pa. Filed Mar.29, 1960, Ser. No. 18,386

6 Claims. (Cl. 32-46) This invention comprises a dental instrument, andmore particularly a dental instrument for effecting a wide variety ofcutting actions.

. This invention has as an object the provision of a novel dentalinstrument.

v This invention has as another object the provision of an oscillatingcutter which may be adapted during the course of the cutting operationto conform with different angles of the surface being worked on, withlittle or no change in the'position of the handpiece,whereby the extentof pain and discomfort experienced by the patient is minimized.

This invention has as yet another object the provision of a dentalinstrument in which an oscillating movement of a cutting tool isachieved without any appreciable internal olf balance displacement ofthe rotating portion of the instrument, such as is commonly referred toVas hum, whereby the operator of such instrument mayY employ the samewith the maximum amount ofl digital sensitivity orffeel. v

.Other objects will appear hereinafter.

r` For the purpose of illustrating the invention there is shown in thedrawings a form which is presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

`Referring to the drawings wherein like reference characters refer tolike parts: A

FIGURE 1l is a vertical sectional view through the dental instrument ofthe present invention, with the cutting tip being disposed in itsoutermost disposition.

, FIGURE 2 is a view similar tothat of FIGURE l, but with the cuttingtip being disposed in its innermost disposition. I

FIGURE 3 is a cross-sectional view taken o-nyline '3l- 3V ofFIGURE l. 1'f l n FIGURE 4 is a fragmentary perspective view revealing the outerand inner `throws at the end of the drive shaft. FIGURE' Slis. afragmentary-.view revealing the vaccommodationof. the cutting tip toasurface being worked u on.

pThe dental instrument of the present invention is designated generallyas and comprises the drive shaft 12 disposed within the handle :14.

The drive shaft 12 may be operatively engaged with the spindle (notshown) of a conventional dental unit by conventional means. A widevariety of such means for operatively engaging the drive shaft of adental instrument with a dental unit are known, and accordingly the sameneed not be illustrated herein.

The drive shaft 12, which has a true circular crosssection, is guided bythe bearing surface 16 on the interior of the handle 14, so that thedrive shaft 12 may rotate at high speed about its center line designated18.

The handle 14 of dental instrument 10 is provided with a bored T-shapedhead 20 at its outer end. The T- shaped head 20 comprises the bore 22which is perpendicularly disposed in respect to and `in communicationwith the bore 24 of the remainder of the handle 14. The outer surface ofthe T-shaped head 20 on either side of the remainder of the handle 14 isprovided with male threads onto which are threadably secured the caps 26and 2S. The cap 26 is imperforate, but the cap 28 is provided with anopening which serves as a bearing, as will be more fully explainedbelow.

A balance bushing 30 is provided within the bore 22 of T-shaped head 20.The balance bushing 30 is machined to a high degree of polish so that itmay be smoothly reciprocated within the bore 22 of T-shaped head 20.

The wall of the balance bushing 30 is slotted for an arcuate length ofapproximately one hundred and eighty degrees or somewhat less than onehundred and eighty degrees to form the slot 32. The axial height of theslot 32 is suicient to receive the inner throw 34 on the outer end ofthe drive shaft 12. The axial height of the slot 32 is sulcient topermit the entry of the outer throw 36 of the drive shaft 12 through thewall of the balance bushing 30 and into the slot 38 of the tool holder40.

The tool holder 40 comprises a cylindrical rod having a highly polishedsurface which is smoothly received within the balance bushing 30 andsmoothly guided by the bearing surface 42 at the end of the balancebushing '30 adjacent the cap 26 and by the bearing surface 44 whichforms the wall of the aperture of the cap 28. The bearing surfaces 42and 44 enable the tool holder 40 to be smoothly reciprocated upon therotation of the drive shaft 12 as will be explained below.

vThe center line 46 of the inner throw 34 and the center line 48 of theouter throw 36 are oppositely disposed in respect to the center line 18of the drive shaft 12 and are equidistant therefrom. Thus, the rotationof the drive shaft 12 is balanced notwithstanding the opposite throws 34and 36.

The tool holder 40 is provided with a threaded socket 50 at its endwhich is received within the bearing surface 44. The matingly threadedend 52 of the cutting tip 54 is threadably received within the threadedsocket 50. The cutting tip 54 may be secured in position by the knurledlock nut 56. Alternatively, a collet or other clamping means may be usedto hold the cutting tip in position. p

A wide variety of cutting tips may be utilized in the dental instrument10 of the present invention. In the illustrated embodiment the cuttingtip comprises a corrugated file-like surface 58, but it is to beunderstood that' a wide variety-of cutting surfaces may be utilized.More-y over, while in the illustrated embodimentthe cutting tip54'comprises a straight member, it is to be understood that offset orangular cutting tips `may be utilized. l

- The operation of the dental instrument 10 of ent invention is asfollows:

'I Upon rotation of the drive shaft 12, thel innerl throw 34 urges thebalance bushing 30 in a direction opposite to the direction which theouter throw 36 urges the tool holder 40. As heretofore noted, the centerlines 46 and 48 of the inner and outer throws 34 and 36 are oppositelyequidistant from the center line 18 of the drive shaft 12. The rotationof the drive shaft 12 is balanced, and moreover the reciprocation of thecutting tip 54 is smooth and balanced because while the balance bushing30 is being urged in one direction the tool holder 40 and the cuttingtip 54 are being urged in the opposite direction. This may beascertained from a comparison of FIG- URES l and 2 which disclose thecutting tip 54 in its outermost disposition and its innermostdisposition respectively. It will be seen that when the cutting tip 54is in its outermost disposition, the balance bushing 30 is in itsdisposition in which it is most closely adjacent to the cap 26. On theother hand, when the cutting tip 54 is in its innermost disposition, thebalance bushing 30 is in its disposition where it is most closelyadjacent to the cap 28. In this manner, balancing of the masses beingmoved is achieved.

The smooth facile operation of the dental instrument 10 permits closedigital control and feel to be achieved the pres- A bythe operator ofthe instrument, since the same is not interferedV with by the hum whichnormally arises from unbalanced vibrations when an eccentric changes itsrotational movement to oscillating or reciprocating movement.

The presence ofthejslots 32 and 38 in the balance bushing 30faud1toolholder 40 respectively permit the cutting tip tobernoved duringoperation so as' to conform with different angles of thesurface beingworked upon. This is shown'in FIGURE 5 wherein it is seen th-at when thecutting,` tip 54`` is utilized on an arcuatesurface, the cutting tip 54may change itsV disposition from that shown in its center dispositiontothat shown in the phantom line dispositions. This permits` the operatorof the dental instrument to follow` a/c'urved or irregular surfacewithout theneces'sity'for shutting off the dental instrument 10 andmakingY vrepeatedV adjustments. Moreover, this enables the operato-r toAeiectworking on surfaces whose irregularity is such that presetadjustment would prove difcultor impossible.

While thee/instrument of the present invention has been described as -adental instrument, it is of course to be understood that itrnay beutilized for a wide variety of other precision Workingmanipulations,such as on jewelry, detail work in models, etc.

`'The present invention may be embodied in'other speciic forms withoutdeparting. fromthe spirit or essential attributes thereof and,accordingly, reference should be made to thexappended claims, ratherthan tothe foregoing specification as indicating fthe scope of theinvention.

, l.. dental instrument including al tubular handle, a bored'headdisposed at the end of said handle, a drive shaft rotatablyA receivedwithin` said handle, aninner throw and an outer throw at the outer en dof s aid drive shaft projecting into said bored head, a balance bushingreciprocally mounted within said bored head, and a tool holderYreciprocally mounted Within` and guided by said balance bushing, withsaid inner throw being operatively engaged with saidbalance, bushingandlsaid outer throw being operatively erigaged with said tool holder.

v 2. Adental instrument inaccordance with claim l in which the'centerlines of Ythe inner and outerv throws are oppositely equidistantly.disposed from the center line of the drivershaft.

's'. A dental instrument including a tubular handle,v a bored headdisposed at theend of said handle,.a drive shaft rotatably receivedwithin said handle, an eccentric at the outer end of said ,drive shaftprojecting intosaid bored head, atool holderreciprocally mounted in saidbored head, a wall of said tool holderbeing slotted by an arcuate lslotwhich extends for an appreciable portion of the periphery of said toolholder, -said eccentric being opera tively engaged with -said toolholder by communicating with walls of said slot in said tool holder,with the lateral dimensions of said slot being appreciably greater thanthe lateral dimensions of said eccentric, whereby upon rotation of saiddrive shaft said toolV holder is reciprocat'ed in respect to saidboredhead and may simultaneously be partially rotated in respect ,tosaidfboredV head.

4. A dental instrument includinga tubular handle, a bored head disposedat the end of` said handle, a drive shaft rotatably received within saidhandle, oppositely disposed throws at the outer end of said drive shaftprojectl ing into said bored head, a balance bushing reciprocallymounted within said bored head, a wall of said balance bushingbeingslotted by an arcuate slot which extendsy for an appreciableportion of the periphery of said balance bushing and whose lateraldimensions are appreciably greater than v.the lateral dimensions ofeither of the oppositely disposed throws, oneof saidoppositely'disposedthrows beingoperatively engaged with said balance bushing bycommunicating with walls of said slot in said bal ance bushing, a'toolholder reciprocally mounted in said bored head to reciprocate in anopposite direction in respect. to the direction of reciprocation of saidbalance bushing, a wall of said tool holderv being slotted by an arcuateslot which extends for an appreciable portion of the periphery of saidtool holder, with the lateral dimensions of lsaid arcuate slot in thewall of said tool holder being appreciablyfgr'leater than the lateralAdimensions' of eitherof said oppositely disposed throws, the other ofsaid `oppositely disposed Vthrows 'being operatively engagedv with` saidtool holder by communicating with walls of said slot vinY said toolholder, lwhereby upon rotation of said drive shaft said tool holder .isreciproated in respect to said bored heady and may simultaneously bepartially rotated in re spect to said bored head.

.5. A dental'instrument in accordance with claim 4 in which the centerlines of the oppositely disposed throws are oppositely equidistantfromthe center line of the drive shaft.

6.l A Vdental instrument in accordance with claim 5 in which theoppositely disposed throws comprise yinner andouterthrows, and in whichthe inner'throw is operatively engagediwith Walls of'the slot 'ofthebalance bushing and in lwhich fthe outer lthrow'is operatively engagedwith walls of the slot of the tool holder.

Fleury et al. Aug. 26, 1890 Eberly Dec. 6, 1938

1. A DENTAL INSTRUMENT INCLUDING A TUBULAR HANDLE, A BORED HEAD DISPOSEDAT THE END OF SAID HANDLE, A DRIVE SHAFT ROTATABLY RECEIVED WITHIN SAIDHANDLE, AN INNER THROW AND AN OUTER THROW AT THE OUTER END OF SAID DRIVESHAFT PROJECTING INTO SAID BORED HEAD, A BALANCE BUSHING RECIPROCALLYMOUNTED WITHIN SAID BORED HEAD, AND A TOOL HOLDER RECIPROCALLY MOUNTEDWITHIN AND GUIDED BY SAID BALANCE BUSHING, WITH SAID INNER THROW BEINGOPERATIVELY ENGAGED WITH SAID BALANCE BUSHING AND SAID OUTER THROW BEINGOPERATIVELY ENGAGED WITH SAID TOOL HOLDER.